Russian Seraphinite — Chatoyant Clinochlore from the Korshunovskoye Deposit
Russian Seraphinite — Chatoyant Clinochlore from the Korshunovskoye Deposit
A trade-name variety of a chlorite-group mineral, named for its angel-feather pattern
Russian seraphinite is the trade name for a chatoyant variety of clinochlore, a chlorite-group mineral, mined commercially only from the Korshunovskoye iron deposit in the Irkutsk region near Lake Baikal. The material is opaque, deep green, and shows silvery to pearlescent fibrous bands of mica-like inclusions whose feather pattern gave rise to the trade name. Seraphinite has no major source outside the Russian Korshunovskoye workings, which gives it an unusually clean origin story: when the trade refers to seraphinite it is, in practice, referring to material from a single deposit.
Mineralogy
Clinochlore is a magnesium-aluminium silicate of the chlorite group, with composition (Mg,Fe2+)5Al(Si3Al)O10(OH)8. It is monoclinic, with a hardness of approximately 2 to 2.5 on the Mohs scale and specific gravity around 2.6 to 2.85. The chatoyant fibrous habit that defines seraphinite is produced by intergrown mica platelets — typically of biotite or muscovite character — whose silvery reflectivity contrasts against the dark green clinochlore matrix. The result is a banded, feathery pattern that, when properly oriented, suggests the imagery of feathers or wings; the trade name seraphinite derives from the seraphim of Christian iconography.
Refractive index for clinochlore falls in the 1.57 to 1.59 range, but seraphinite is essentially never tested by refractometer because the material is opaque and is cut almost exclusively as cabochon. Identification in trade is by visual character supplemented by hardness and specific gravity testing, both of which place the material clearly in the chlorite group.
The Korshunovskoye deposit
The Korshunovskoye deposit is principally an iron ore mine, with seraphinite occurring as a secondary mineral in the surrounding metamorphic and metasomatic zones. Production is small relative to the iron operation, and seraphinite is extracted on a scale that supports a steady but limited cabochon-cutting industry. Material from this single source has supplied substantially all the seraphinite reaching the international gem trade since the variety was named in the late twentieth century.
Other chlorite-group materials with comparable visual character — chatoyant green chlorite from various Russian, Ukrainian, and Brazilian localities — occasionally enter the market under inaccurate trade names, but the trade convention reserves seraphinite for Korshunovskoye material specifically.
Cutting and durability
At hardness 2 to 2.5, seraphinite is among the softer materials regularly used in jewellery, comparable in scratch resistance to gypsum and softer than fingernail. The material does not take a high polish in the way harder cabochon stones do, and the surface is sensitive to abrasion in everyday wear. Cutters orient the rough so that the fibrous bands present face-up across the dome of the cabochon, maximising the play of the chatoyant pattern. Slabs are cut for ornamental objects, beads, and pendant work; ring use is generally inadvisable in any setting that exposes the stone to friction.
Seraphinite jewellery is best suited to pendants, earrings, and brooches, with bezel settings preferred over prong work both for the visual presentation and for protective reasons. Cleansing should be by mild soap and warm water with a soft cloth; ultrasonic and steam cleaning are not appropriate, and chemical cleaners should be avoided. The stone is sensitive to thermal shock and should not be exposed to abrupt temperature changes.
In the trade
Seraphinite occupies a niche in the collector and ornamental-stone market. Pricing is modest relative to the major coloured stones, with the principal driver of value being the clarity and pattern of the chatoyant bands rather than weight or size. The most desirable cabochons show distinct, well-defined silvery feathers across a uniformly deep green matrix, with minimal matrix breaks or dead zones. Cabochons of even quality in the 10 to 25 carat range are the working size for most pendant and earring designs.
The material is documented by GIA and the International Gem Society as a chlorite-group variety, and the Korshunovskoye-specific trade convention is widely respected in established trade. Buyers should expect Russian seraphinite to be sold as a Korshunovskoye-origin material; representations of seraphinite from other sources should be treated with appropriate caution.